Predicting factors for liver iron overload at the first magnetic resonance in children with thalassaemia major

Abstract

Background. Transfusion dependency determines iron overload in thalassaemia major, with devastating complications. Significant liver iron overload has been observed from early childhood and we aimed to evaluate factors that could predict liver iron overload at the first magnetic resonance imaging (MRI).
Materials and methods. All transfusion-dependent children who underwent MRI to assess iron overload were retrospectively studied. Age, weight, height, blood requirement, chelation drug and dosage, serum ferritin and liver enzymes were evaluated at three specific steps: start of transfusion regimen, start of chelation therapy, and first MRI.
Results. Among 198 patients, 25 children met inclusion criteria. No differences were detected in all the assessed parameters at start of transfusion regimen and chelation therapy (p>0.05) between patients with good iron balance (liver iron concentration [LIC] <7 mg Fe/g dry weight [dw]) and liver iron overload (LIC >7). At the first MRI, patients with iron overload had significantly higher serum ferritin (3,080.3±1,078.5 vs 1,672.0±705.3 ng/mL; p<0.01) while patients with good iron control maintained a stable ferritin value from the start of chelation therapy but showed significantly lower height Z-score (−1.48±1.02 vs -0.36±1.55; p=0.04). Serum ferritin >1,770 ng/mL was detected as the best threshold for predicting liver iron overload at the first MRI (p=0.0003).
Conclusion. In order to prevent liver iron overload at the first MRI, children should maintain a stable level of serum ferritin below 1,770 from the start of chelation therapy. However, strict monitoring of growth is mandatory.